Aquaculture: Management, Challenges and Developments

Effects of Protein, Lipid, Feeding Levels and Their Interaction ... 69

 Specific growth rate (SGR) = 100 (in final mean weight- in initial

mean weight)/days

 Feed efficiency (FE %) = 100 x (wet weight gain of fish)/dry weight

of fish consumed

 Protein efficiency ratio (PER) = weight gain x 100/protein intake

 Protein intake (PI) = crude protein level/100 x feed intake

 Viscerasomatic index (VSI) = 100 x (viscera weight)/(body weight)

 Hepatosomatic index (HIS) = 100 x (liver weight)/(body weight)

 Intraperitoneal fat (IPF) = 100 x (intraperitoneal fat weight)/(body

weight)

 Intestineal length ration (ILR) = intestine length/body length

The data was analysed using STATISTICA computer package (Statsoft
Inc., 2010, version 8.0). Before statistical analysis, normality of the data was
determined using Shapiro-Wilk test, while homogeneity of variance was
ascertained using Levene’s test. The results were presented as mean ± standard
error after subjecting the data to three way ANOVA followed by one-way
ANOVA using Dancan multiple range test. The difference was considered
significant at p < 0.05, p < 0.01 and p < 0.001 based on the threshold of each
interaction.

RESULTS

The main effects of crude protein, crude lipid and feeding rate on growth
parameters at the end of 4 months are shown in Table 2. At the end of 16
weeks study period, neither mortality nor external clinical symptoms occurred
in any treatment during the period of this study. Higher WG%, FE and SGR
was observed in H35 treatment and it was significantly different (p < 0.01)
from H25 treatment. However, higher FI was noted in H25 treatment but it
was not significantly different (p > 0.05) from H35 treatment. Higher WG%,
SGR and FI was observed in L8 treatment and it was significantly different (p
< 0.001) from L12 treatments. Notably, FE (%) was higher in L8 treatment but
it was not significantly different (p > 0.05) from L12 treatment. With regard to
the feeding rate, significantly higher (p < 0.01) WG%, SGR and FI was
recorded in H100 and it was significantly different (p< 0.05) from M70 and
L50 treatments. However, higher FE was recorded in L50 and it was
significantly different (p < 0.01) from H100 but not significantly different